Question

Differentiate between melting of wax and burning of a wax candle .

Answer 1

Differences between melting of wax and burning of a wax candle are-

Melting of wax	Burning of a wax
It is a physical change (as it is a change in state of matter that may be reversed)	Burning of wax is a chemical change because this carbon can't be turned back into wax, it's a chemical alteration.
It involves change of solid wax to liquid state on heating.	It involves formation of new compounds like Carbon dioxide, water etc. as a part of chemical change.
These are temporary changes.	It is a permanent change and can not be reversed back.
No change in chemical composition of a substance takes place.	Candle wax is made up of hydrocarbons which on burning produce different type of gases. $\underset{\mathrm{Wax}\left(\mathrm{fuel}\right)}{{\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2n+2}\left(\mathrm{g}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)}$